/*
 * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

package org.eclipse.imagen.operator;

import java.awt.RenderingHints;
import java.awt.image.RenderedImage;
import java.awt.image.SampleModel;
import java.awt.image.renderable.ParameterBlock;
import java.awt.image.renderable.RenderableImage;
import org.eclipse.imagen.JAI;
import org.eclipse.imagen.OperationDescriptorImpl;
import org.eclipse.imagen.ParameterBlockJAI;
import org.eclipse.imagen.RenderableOp;
import org.eclipse.imagen.RenderedOp;
import org.eclipse.imagen.registry.RenderableRegistryMode;
import org.eclipse.imagen.registry.RenderedRegistryMode;

/**
 * An <code>OperationDescriptor</code> describing the "Overlay" operation.
 *
 * <p>The Overlay operation takes two rendered or renderable source images, and overlays the second source image on top
 * of the first source image. No additional parameters are required.
 *
 * <p>The two source images must have the same data type and number of bands. However, their <code>SampleModel</code>
 * types may differ. The destination image will always have the same bounding rectangle as the first source image, that
 * is, the image on the bottom, and the same data type and number of bands as the two sources. In case the two sources
 * don't intersect, the destination will be the same as the first source.
 *
 * <p>The destination pixel values are defined by the pseudocode:
 *
 * <pre>
 * if (srcs[1] contains the point (x, y)) {
 *     dst[x][y][b] = srcs[1][x][y][b];
 * } else {
 *     dst[x][y][b] = srcs[0][x][y][b];
 * }
 * </pre>
 *
 * <p>
 *
 * <table border=1>
 * <caption>Resource List</caption>
 * <tr><th>Name</th>        <th>Value</th></tr>
 * <tr><td>GlobalName</td>  <td>Overlay</td></tr>
 * <tr><td>LocalName</td>   <td>Overlay</td></tr>
 * <tr><td>Vendor</td>      <td>org.eclipse.imagen.media</td></tr>
 * <tr><td>Description</td> <td>Overlays one image on top of
 *                              another.</td></tr>
 * <tr><td>DocURL</td>      <td>http://java.sun.com/products/java-media/jai/forDevelopers/jai-apidocs/javax/media/jai/operator/OverlayDescriptor.html</td></tr>
 * <tr><td>Version</td>     <td>1.0</td></tr>
 * </table>
 *
 * <p>No parameters are needed for this operation.
 *
 * @see org.eclipse.imagen.OperationDescriptor
 */
public class OverlayDescriptor extends OperationDescriptorImpl {

    /**
     * The resource strings that provide the general documentation and specify the parameter list for this operation.
     */
    private static final String[][] resources = {
        {"GlobalName", "Overlay"},
        {"LocalName", "Overlay"},
        {"Vendor", "org.eclipse.imagen.media"},
        {"Description", JaiI18N.getString("OverlayDescriptor0")},
        {
            "DocURL",
            "http://java.sun.com/products/java-media/jai/forDevelopers/jai-apidocs/javax/media/jai/operator/OverlayDescriptor.html"
        },
        {"Version", JaiI18N.getString("DescriptorVersion")}
    };

    private static final String[] supportedModes = {"rendered", "renderable"};

    /** Constructor. */
    public OverlayDescriptor() {
        super(resources, supportedModes, 2, null, null, null, null);
    }

    /**
     * Validates the input sources.
     *
     * <p>In addition to the standard checks performed by the superclass method, this method checks that the source
     * image <code>SampleModel</code>s have the same number of bands and transfer types.
     */
    protected boolean validateSources(String modeName, ParameterBlock args, StringBuffer msg) {
        if (!super.validateSources(modeName, args, msg)) {
            return false;
        }

        if (!modeName.equalsIgnoreCase("rendered")) return true;

        RenderedImage src1 = args.getRenderedSource(0);
        RenderedImage src2 = args.getRenderedSource(1);

        SampleModel s1sm = src1.getSampleModel();
        SampleModel s2sm = src2.getSampleModel();

        if (s1sm.getNumBands() != s2sm.getNumBands() || s1sm.getTransferType() != s2sm.getTransferType()) {
            msg.append(getName() + " " + JaiI18N.getString("OverlayDescriptor1"));
            return false;
        }

        return true;
    }

    /**
     * Overlays one image on top of another.
     *
     * <p>Creates a <code>ParameterBlockJAI</code> from all supplied arguments except <code>hints</code> and invokes
     * {@link JAI#create(String,ParameterBlock,RenderingHints)}.
     *
     * @see JAI
     * @see ParameterBlockJAI
     * @see RenderedOp
     * @param source0 <code>RenderedImage</code> source 0.
     * @param source1 <code>RenderedImage</code> source 1.
     * @param hints The <code>RenderingHints</code> to use. May be <code>null</code>.
     * @return The <code>RenderedOp</code> destination.
     * @throws IllegalArgumentException if <code>source0</code> is <code>null</code>.
     * @throws IllegalArgumentException if <code>source1</code> is <code>null</code>.
     */
    public static RenderedOp create(RenderedImage source0, RenderedImage source1, RenderingHints hints) {
        ParameterBlockJAI pb = new ParameterBlockJAI("Overlay", RenderedRegistryMode.MODE_NAME);

        pb.setSource("source0", source0);
        pb.setSource("source1", source1);

        return JAI.create("Overlay", pb, hints);
    }

    /**
     * Overlays one image on top of another.
     *
     * <p>Creates a <code>ParameterBlockJAI</code> from all supplied arguments except <code>hints</code> and invokes
     * {@link JAI#createRenderable(String,ParameterBlock,RenderingHints)}.
     *
     * @see JAI
     * @see ParameterBlockJAI
     * @see RenderableOp
     * @param source0 <code>RenderableImage</code> source 0.
     * @param source1 <code>RenderableImage</code> source 1.
     * @param hints The <code>RenderingHints</code> to use. May be <code>null</code>.
     * @return The <code>RenderableOp</code> destination.
     * @throws IllegalArgumentException if <code>source0</code> is <code>null</code>.
     * @throws IllegalArgumentException if <code>source1</code> is <code>null</code>.
     */
    public static RenderableOp createRenderable(
            RenderableImage source0, RenderableImage source1, RenderingHints hints) {
        ParameterBlockJAI pb = new ParameterBlockJAI("Overlay", RenderableRegistryMode.MODE_NAME);

        pb.setSource("source0", source0);
        pb.setSource("source1", source1);

        return JAI.createRenderable("Overlay", pb, hints);
    }
}
